The present invention relates to an optical fiber cable capable of withstanding a jump in temperature to 350.degree. C. for a short period of time, the cable comprising: (a) at least one carrier element of a composite of glass fiber and thermosetting resin; (b) an optical fiber support constituted by a grooved rod surrounding the carrier element, or a tube preferably provided with carrier elements in its thickness, or by compact structure fibers, the rod or tube being made of a thermoplastic polymer; (c) optical fibers disposed in the grooves of the rod or inside the tube; (d) a viscous material filling the grooves or the tube around the optical fibers; (e) an envelope constituted by a tape of thermoplastic polymer. Such cables are required, in particular as guard cables for high or medium tension electric cables which are subjected to high fault currents due to strokes of lightning or to short circuits. It has been observed that these fault currents may raise the temperature of optical cable fibers disposed in the vicinity to 300.degree. C. or 350.degree. C. for several seconds or several tens of seconds.
To this end, proposals have already been made for compact structure optical fiber cables based on silicone resins. However, such cables cannot withstand large amounts of elongation.
Proposals have also been made for cables including a core constituted by a grooved aluminum or light alloy rod together with optical fibers that are covered by means of a fluorine-containing resin. However, manufacturing a light alloy or aluminum rod requires special tooling which is more expensive than the usual tooling.
The object of the present invention is to provide an optical fiber cable capable of withstanding jumps in temperature to 300.degree. C. to 350.degree. C., which lends itself, in addition, to large amounts of elongation, but which is manufactured using a method and apparatus analogous to those used for ordinary optical fiber cables.